Maintaining pressure input paths
A method of maintaining a pressure input path in a sensing array is described. The sensing array comprises a plurality of sensing elements, and the method involves activating a first sensing element to determine a first location data point and activating a second sensing element to determine a second location data point. The state location (x,y) and state velocity (V x , V y ) are calculated based on the first and second location data points to create a state vector. A predicted path of further location data points is determined from the state vector to avoid drop out problems with pressure inputs.
1. A method of maintaining a pressure input path in a sensing array, said sensing array comprising a plurality of sensing elements, said method comprising the steps of:
activating a first sensing element to determine a first location data point;
activating a second sensing element to determine a second location data point;
calculating a state location and a state velocity based on said first location data point and said second location data point to create a state vector;
determining a predicted path of at least one further location data point from said state vector;
updating said state vector by replacing an earlier location data point with a later location data point derived from activation of a further sensing element;
utilizing said predicted path to provide a continuous pressure input path to prevent drop out of an input gesture; and
terminating said predicted path following a predetermined time period in which no further sensing elements have been activated.
2. The method of claim 1 , wherein each said location data point comprises two-dimensional positional data.
3. The method of claim 1 , wherein each said location data point comprises a measurement of applied pressure.
4. The method of claim 1 , further comprising the step of:
updating said state vector by recalculating said state velocity in respect of said second location data point and a third location data point.
5. The method of claim 1 , wherein said step of determining said predicted path comprises extrapolating said location data points to predict a further location data point.
6. The method of claim 1 , further comprising the step of:
scanning said sensing array absent of any activated sensing elements to determine a background reading; and
removing said background reading when determining said location data points.
7. The method of claim 1 , further comprising the step of:
performing a smoothing process to data points in said predicted path.
8. An apparatus for maintaining a pressure input, comprising:
a sensing array comprising a plurality of sensing elements; and
a processor configured to:
determine a first location data point in response to activation of a first sensing element;
determine a second location data point in response to activation of a second sensing element;
calculate a state location and state velocity based on said first location data point and said second location data point to create a state vector;
determine a predicted path of at least one further location data point based on said state vector;
update said state vector by replacing an earlier location data point with a later location data point derived from activation of a further sensing element;
utilize said predicted path to provide a continuous pressure input path to prevent drop out of an input gesture; and
terminate said predicted path following a predetermined time period in which no further sensing elements have been activated.
9. The apparatus of claim 8 , wherein said sensing elements comprise a pressure sensitive material responsive to an applied pressure.
10. The apparatus of claim 8 , wherein said sensing array is configured to provide two-dimensional positional data and an extent property in response to an applied pressure.
11. A touch screen comprising the apparatus of claim 8 .
12. An electronic device comprising the touch screen of claim 11 .
13. A method of maintaining a pressure input path in a sensing array, said sensing array comprising a plurality of sensing elements, said method comprising the steps of:
scanning said sensing array absent of any activated sensing elements to determine a background reading; and
activating a first sensing element and removing said background reading to determine a first location data point;
activating a second sensing element and removing said background reading to determine a second location data point;
calculating a state location and a state velocity based on said first location data point and said second location data point to create a state vector;
determining a predicted path of at least one further location data point from said state vector;
utilizing said predicted path to provide a continuous pressure input path to prevent drop out of an input gesture; and
terminating said predicted path following a predetermined time period in which no further sensing elements have been activated.
14. The method of claim 13 , wherein each said location data point comprises two-dimensional positional data.
15. The method of claim 13 , wherein each said location data point comprises a measurement of applied pressure.
16. The method of claim 13 , further comprising the step of:
updating said state vector by recalculating said state velocity in respect of said second location data point and a third location data point.
17. The method of claim 13 , wherein said step of determining said predicted path comprises extrapolating said location data points to predict a further location data point.
18. The method of claim 13 , further comprising the step of:
performing a smoothing process to data points in said predicted path.